in Congress of the International Society of Thrombosis and Hemostasis- 57th Annual SSC Meeting (2011, July)

Atherosclerosis is the principal cause of mortality in industrialized countries. Its development is influenced by several mediators of which thromboxane A(2) (TXA(2)) and 8-iso-PGF(2() have recently ... [more ▼]

Atherosclerosis is the principal cause of mortality in industrialized countries. Its development is influenced by several mediators of which thromboxane A(2) (TXA(2)) and 8-iso-PGF(2() have recently received a lot of attention. This study aimed to investigate the effect of a dual thromboxane synthase inhibitor and thromboxane receptor antagonist (BM-573) and ASA on lesion formation in apolipoprotein E-deficient mice. The combination of ASA and BM-573 was also studied. Plasma measurements demonstrated that the treatments did not affect body weight or plasma cholesterol levels. BM-573, but not ASA, significantly decreased atherogenic lesions as demonstrated by macroscopic analysis. Both treatments alone inhibited TXB(2) synthesis but only BM-573 and the combination therapy were able to decrease firstly, plasma levels of soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) and secondly, the expression of these proteins in the aortic root of Apo E. These results were confirmed in endothelial cell cultures derived from human saphenous vein endothelial cells (HSVECs). In these cells, BM-573 also prevented the increased mRNA expression of ICAM-1 and VCAM-1 induced by U-46619 and 8-iso-PGF(2(). Our results show that a molecule combining receptor antagonism and thromboxane synthase inhibition is more efficient in delaying atherosclerosis in Apo E(-/-) mice than sole inhibition of TXA(2) formation. [less ▲]

Atherosclerosis is the principal cause of mortality in industrialized countries. Its development is influenced by several mediators of which thromboxane A(2) (TXA(2)) and 8-iso-PGF(2() have recently ... [more ▼]

Atherosclerosis is the principal cause of mortality in industrialized countries. Its development is influenced by several mediators of which thromboxane A(2) (TXA(2)) and 8-iso-PGF(2() have recently received a lot of attention. This study aimed to investigate the effect of a dual thromboxane synthase inhibitor and thromboxane receptor antagonist (BM-573) and ASA on lesion formation in apolipoprotein E-deficient mice. The combination of ASA and BM-573 was also studied. Plasma measurements demonstrated that the treatments did not affect body weight or plasma cholesterol levels. BM-573, but not ASA, significantly decreased atherogenic lesions as demonstrated by macroscopic analysis. Both treatments alone inhibited TXB(2) synthesis but only BM-573 and the combination therapy were able to decrease firstly, plasma levels of soluble intracellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) and secondly, the expression of these proteins in the aortic root of Apo E. These results were confirmed in endothelial cell cultures derived from human saphenous vein endothelial cells (HSVECs). In these cells, BM-573 also prevented the increased mRNA expression of ICAM-1 and VCAM-1 induced by U-46619 and 8-iso-PGF(2(). Our results show that a molecule combining receptor antagonism and thromboxane synthase inhibition is more efficient in delaying atherosclerosis in Apo E(-/-) mice than sole inhibition of TXA(2) formation. [less ▲]

Atherosclerosis is a chronic vascular disease whose development is influenced by several mediators 1. Among them, the prostanoids large family lipids generated from the metabolism of arachidonic acid by ... [more ▼]

Atherosclerosis is a chronic vascular disease whose development is influenced by several mediators 1. Among them, the prostanoids large family lipids generated from the metabolism of arachidonic acid by the action of COX includes various types of PGs and thromboxane. Thromboxane A2 and PGI2 are present in abnormally elevated concentration in atherosclerosis 2-3. To exert its effects TXA2 and its precursor PGH2 act at a specific receptor termed TP receptor 4. As a result, TXA2 synthase inhibitors and TP antagonists have been developed to reduce and to prevent TXA2 production and actions, respectively. The present study was undertaken in order to investigate whether BM-573, an original sulfonylurea derivate synthesized in our lab 5, and aspirin would be effective in preventing the progression of atherosclerosis in an apo E deficient mouse model. [less ▲]

To test the efficacy of BM-573 in atherogenesis, the effect of 10 weeks of treatment with BM573 (10 mg/l) on early aortic atherosclerotic lesions of apo E deficient mice was assessed. These mice were fed ... [more ▼]

To test the efficacy of BM-573 in atherogenesis, the effect of 10 weeks of treatment with BM573 (10 mg/l) on early aortic atherosclerotic lesions of apo E deficient mice was assessed. These mice were fed with chow diet, with spontaneous increase of total plasma cholesterol and triglycerides. In this experiment, while BM-573 did not affect body weight, it significantly decreases early atherogenesis lesions confirmed by macroscopic, microscopic and biochemical analysis. These results confirm that selective antagonism of TP receptor is effective in reducing atherosclerotic lesion in apo E deficient mice. Consequently, BM-573 could be a potential drug for prevention of atherosclerosis [less ▲]

Atherosclerotic cardiovascular disease, according to World Health Organization, is the primary cause of heart disease and stroke. Atherosclerosis is a chronic vascular disease whose development is ... [more ▼]

Atherosclerotic cardiovascular disease, according to World Health Organization, is the primary cause of heart disease and stroke. Atherosclerosis is a chronic vascular disease whose development is influenced by several mediators. Among them, the action of eicosanoïds such as thromboxane A2 and 8-iso-PGF2a have recently received a lot of attention. The aim of our study was the evaluation of benefits of original molecules, synthesised in our lab, targeting the thromboxane receptor (TP) in an apo E deficient mouse. We previously demonstrated in several in vitro and in vivo pharmacological experiments that our original sulfonylurea derivate, BM-573 was a potent combined inhibitor of the thromboxane synthase and antagonist of TP. Since TP is implied in atherosclerosis development, such antagonist could have a great therapeutic impact in atherogenesis.To test the efficacy of BM-573 in atherogenesis, the effect of 10 weeks of treatment with BM573 (10 mg/kg) on early aortic atherosclerotic lesions of apo E deficient mice was assessed. These mice were fed with chow diet, with spontaneous increase of total plasma cholesterol and triglycerides. In this experiment, while BM-573 did not affect body weight, it significantly decreased early atherogenesis lesions confirmed by macroscopic, microscopic and biochemical analysis. These results confirm that selective antagonism of TP receptor is effective in reducing atherosclerotic lesion in apo E deficient mice. Consequently, BM-573 could be a potential drug for prevention of atherosclerosis. [less ▲]

Although reperfusion after coronary occlusion is mandatory for myocardial salvage, reperfusion may trigger a cascade of harmful events (reperfusion injury) adding to myocardial injury. We investigated ... [more ▼]

Although reperfusion after coronary occlusion is mandatory for myocardial salvage, reperfusion may trigger a cascade of harmful events (reperfusion injury) adding to myocardial injury. We investigated effects of reperfusion on left ventricular (LV) haemodynamics and ventriculo-arterial (VA) coupling in pigs following acute myocardial ischaemia induced by coronary artery occlusion. Experiments were performed in six animals, with measurements of cardiac and arterial function at baseline, after 60 min of ischaemia (T60) and after 2 (T180) and 4 h of reperfusion (T300). Ventriculo-arterial coupling was assessed using the ventriculo-arterial elastance ratio of paper, as well as using a 'stiffness coupling' and 'temporal coupling' index. Reperfusion following ischaemia (T180 versus T60) induced a progressive decline in cardiovascular function, evidenced by a decrease in mean arterial blood pressure, cardiac output and ejection fraction which was not restored at T300. Although reperfusion also induced an increase in slope of the end-systolic pressure-volume relationship (ESPVR), the ESPVR curve shifted to the right, associated with a depression of contractile function. Histology demonstrated irreversible myocardial damage at T300. The ventriculo-arterial elastance ratio and the 'stiffness coupling' index were unaffected throughout the protocol, but the 'temporal coupling' parameter indicated a relative shift between heart period and the time constant of the arterial system. It is unlikely that these alterations are attributable to ischaemic injury alone. The combination of both the stiffness and temporal coupling index may provide more information when studying ventriculo-arterial coupling than the more commonly used ventricular end-systolic stiffness/effection arterial elastance (E-es/E-a) ratio. [less ▲]

The aim of our study was to use an apoE–deficient mouse model to test drugs acting as thromboxane A2 antagonist. Presented here is the “en face” method 6 which allows the evaluation of atherosclerosis ... [more ▼]

The aim of our study was to use an apoE–deficient mouse model to test drugs acting as thromboxane A2 antagonist. Presented here is the “en face” method 6 which allows the evaluation of atherosclerosis lesions development in wild type and APO E-/- mice. This method involves pinning out the aorta and quantifying lesion area as a percentage of total surface area. The use of this mice model offers a unique opportunity to characterize the therapeutic benefits of pharmacologicals agents designed in our laboratory of which antioxidants and thromboxane modulators. The pharmacological characterization of BM-573 as potential antiatherosclerotic agent will also be discussed [less ▲]

Rapid restoration of coronary blood flow following a period of myocardial ischemia (due to coronary occlusion) is mandatory to preserve the cardiac muscle. Reperfusion, however, not necessarily restores ... [more ▼]

Rapid restoration of coronary blood flow following a period of myocardial ischemia (due to coronary occlusion) is mandatory to preserve the cardiac muscle. Reperfusion, however, not necessarily restores cardiac function, and cellular damage of the cardiac muscle cells following reperfusion (reperfusion injury) is well documented. The aim of this study was to investigate the effects of reperfusion on left ventricular (LV) hemodynamics and on left ventriculo-arterial (VA) coupling in acutely ischemic pigs. [less ▲]

Background: Great advances have been made in the prevention of thrombotic disorders by developments of new pharmacological and surgical treatments. Animal models of arterial thrombosis have largely ... [more ▼]

Background: Great advances have been made in the prevention of thrombotic disorders by developments of new pharmacological and surgical treatments. Animal models of arterial thrombosis have largely contributed to the discovery and to the validation of original treatments. The purpose of the present work was to develop and validate an original model of acute myocardial infarction provoked in pig by thrombosis of the left anterior descending (LAD) coronary artery induced by topical application of ferric chloride solution. Methods and results: Myocardial infarction, resulting from an occlusive and adherent mixed thrombus formed in the LAD coronary artery, was examined at macroscopic level using dual staining technique (Evans blue dye; triphenyltetrazolium chloride) and at microscopic level using conventional histological analyses and immunohistochemical detection of desmin. Biochemical markers (troponin T and ATP), platelet reactivity and standard hemodynamic parameters (such as stroke volume, ejection fraction, stroke work and cardiac output) have also been evaluated. From these analyses, it was demonstrated that each pig developed a transmural area of irreversible damage mainly located in the anteroseptal region of the left ventricle. The more progressive development of coronary artery occlusion, as compared to an abrupt Ligation, was accompanied by a correspondingly progressive impairment in hemodynamics. Conclusion: We conclude that this original porcine model of myocardial infarction is quite close to clinical pathophysiological conditions, such as thrombus formation occurring after atherosclerotic plaque rupture. This certainly constitutes a further argument in favour of this model to assess pharmaceutical or mechanical support of an acutely ischemic heart. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

BM-573 (N-terbutyl-N'-[2-(4'-methylphenylamino)-5-nitro-benzenesulfonyl]urea), a torsemide derivative, is a novel non-carboxylic dual TXA2 synthase inhibitor and receptor antagonist. The pharmacological profile of the drug is characterized by a higher affinity for the thromboxane receptor than that of SQ-29548, one of the most powerful antagonists described to date, by a complete prevention of human platelet aggregation induced by arachidonic acid at a lower dose than either torsemide or sulotroban, and by a significantly prolonged closure time measured by the platelet function analyser (PFA-100). Moreover, at the concentrations of 1 and 10 microM, BM-573 completely prevented production of TXB2 by human platelets activated by 0.6 mM of arachidonic acid. BM-573 prevents rat fundus contraction induced by U-46619 but not by prostacyclin or other prostaglandins. Despite possessing a chemical structure very similar to that of a diuretic torsemide, BM-573 has no diuretic activity. BM-573 does not prolong bleeding time and, unlike some of the other sulfonylureas, has no effect on blood glucose levels. In vivo, BM-573 appears to have antiplatelet and antithrombotic activities since it reduced thrombus weight and prolonged the time to abdominal aorta occlusion induced by ferric chloride. BM-573 also relaxed rat aorta and guinea pig trachea precontracted with U-46619. In pigs, BM-573 completely antagonized pulmonary hypertensive effects of U-46619 and reduced the early phase of pulmonary hypertension in models of endotoxic shock and pulmonary embolism. Finally, BM-573 protected pigs from myocardial infarction induced by coronary thrombosis. These results suggest that BM-573 should be viewed as a promising therapeutic agent in the treatment of pulmonary hypertension and syndromes associated with platelet activation. [less ▲]

The aim of this work was to evaluate the effects of BM-567 ( N-pentyl-N'-[(2-cyclohexylamino-5-nitrobenzene)sulfonyl]urea), a torasemide derivative. on both thromboxane A(2) (TXA(2)) receptors (TP) and ... [more ▼]

The aim of this work was to evaluate the effects of BM-567 ( N-pentyl-N'-[(2-cyclohexylamino-5-nitrobenzene)sulfonyl]urea), a torasemide derivative. on both thromboxane A(2) (TXA(2)) receptors (TP) and thromboxane synthase of human platelets. The drug affinity for TP receptors of human washed platelets has been determined. In this test BM-567 showed a high affinity (IC50: 1.1+/-0.1 nM) for the TP receptors in comparison with BM-531 (IC50: 7.8+/-0.7 nM) and sulotroban (IC50: 931+/-85 nM), two TXA(2) antagonists. We also demonstrated that BM-567 prevented platelet aggregation induced by arachidonic acid (AA) (600 muM) (ED100: 0.20+/-0.10muM), U-46619, a stable TXA(2) agonist (1 muM) (ED50: 0.30+/-0.04 muM) and collagen (1 mug ml(-1)) (% of inhibition: 44.3+/-4.3% at 10 muM) and inhibited the second wave of ADP (2 muM). Moreover, when BM-567 was incubated in whole blood from healthy donors, the closure time measured by the Platelet Function analyzer (PFA-100) was significantly prolonged (closure time: 215+/-21 s) by using collagen/epinephrine cartridges. Finally, at the concentration of 1 muM, BM-567 completely reduced the TXB2 production from human platelets stimulated with AA (600 muM). These results indicate that BM-567 is a novel combined TXA(2) receptor antagonist and thromboxane synthase inhibitor characterized by a powerful antiplatelet potency. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]